1. Field
One or more embodiments relate to a communication module which sets priority in data transmission by transmitting a preamble signal, and a multi-type air conditioning apparatus using the same, and a control method thereof.
2. Description of the Related Art
A conventional multi-type air conditioning apparatus including a plurality of outdoor units and a plurality of indoor units in an RS-485 communication environment uses a polling method to avoid collision on a communication line.
That is, after one constituent unit of the plural outdoor units and the plural indoor units is set as a master unit and the remaining constituent units are set as slave units, the master unit authorizes the slave units to perform communication in order. That is, each of the slave unit may transmit data only when it is the corresponding slave unit's turn.
Since the master unit authorizes all the slave units to perform communication once, when the number of the slave units increases, the slave units stand by for a long time to occupy the communication line and to perform communication.